The present invention relates to a trunked radio system (TRS), and more particularly, to a local-area-network (LAN) TRS/wide-area-network (WAN) TRS and the operation thereof in which information on the overall mobiles is processed into a data base. Several LANS for controlling a plurality of mobiles and a WAN for connecting and collectively controlling the plurality of LANs are stratified so that respective mobiles are able to receive communication service anywhere in the WAN, and the grading of communication service and the control of transmission signal level are effectively performed.
FIG. 1 shows a configuration of a conventional LAN TRS, with FIG. 2 illustrating the relationship among the conventional LAN TRSs.
First, the conventional LN TRS is composed of a TRS switching system A10, a public switched telephone network (PSTN), wireless voice channels R1-Rm, a control channel CC, and mobiles 1-m. Wireless voice channels R1-Rm provide a path for transmission and reception of a voice signal and data to and from a mobile, and are allocated by control channel CC. Control channel CC transmits the voice signal and data of the mobiles to TRS switching system A10 by means of a wire or a microwave, and transmits the voice and data output from TRS switching system A10 to a corresponding mobile. Control channel CC allocates wireless voice channels R1-Rm to respective mobiles and transmits various data such as location information on the mobiles to TRS switching system A10. TRS switching system A10 controls control channel CC and wireless channels R1-Rm by using the various data of mobiles 1-m so as to enable to communication between the respective mobile and the PSTN.
FIG. 2 shows three nearby LAN TRSs A100, A200 and A300.
Communication among the conventional LAN TRS and a plurality of other LAN TRS will be described below.
Respective LAN systems A100, A200 and A300 control only mobiles registered in the LAN TRS systems and do not provide communication service to mobiles which have migrated from other LAN TRS systems, because respective mobiles registered in one LAN TRS system are able to receive communication service only within a limited area of communication service of that LAN system. In addition, the output of the wireless voice channels of the respective LAN TRS systems is uniformly maintained only for the mobiles concerned, without the effects of other LAN TRS systems being considered.
Accordingly, in a plurality of LAN TRSs A100, A200 and A300, voice signal/data communication passages only are connected between the respective LAN TRS, but there cannot be constructed a WAN TRS for the overall LAN TRSs A100, A200 and A300.
Since such a LAN TRS cannot control the output between the mobiles and wireless voice channels of several LAN TRSs, an interference produced at an overlapping portion of communication service areas of the respective LAN TRSs cannot be prevented, and there is the possibility that communication service may be frequently interrupted inside the limited area of communication service of the respective LAN TRSs. When a mobile registered on a LAN TRS system migrates into the communication service area of other LAN TRS on which the mobile is not registered, and requests communication service, the other LAN TRS doesn't provide communication service to the mobile. Further, if communication service surpasses a limit of capacity in a LAN TRS, an enormous cost is needed for the expansion of capacity.